In recent years, in the field of mobile terminals, mobile terminals have been designed to reduce power consumption thereof from the perspective of increasing lives of batteries. The power consumption when a mobile terminal is connected to the Internet varies depending on communication methods for connecting the mobile terminal to the Internet.
Examples of the communication methods include a communication method for accessing the Internet by a 3rd generation (3G) antenna used for communications with a 3G network, and a communication method for accessing the Internet by a wireless fidelity (Wi-Fi) antenna used for Wi-Fi communications. Between both communication methods, the mobile terminal employing the communication method for accessing the Internet by a Wi-Fi antenna consumes less power.
Therefore, when a mobile terminal is connected to the Internet, the power consumption of the mobile terminal can be reduced by employing Wi-Fi antennas as much as possible for connecting the mobile terminal to the Internet.
Conventionally, such technologies for reducing the power consumption include a technology in which an antenna that can communicate with the Wi-Fi antenna of a mobile terminal, that is, a so-called access point is prepared in a moving object, such as a vehicle, a train, and a ship.
Devices that generate navigation information such as a navigation screen using information including position information, map information, and traffic information have been developed. In the description below, “navigation” may be simply referred to as “navi”. Such a device, for example, acquires each piece of the information including the position information, the map information, and the traffic information from another device, and generates the navigation information using each of the information thus acquired. At this time, the accuracy of each piece of the information including the position information, the map information, and the traffic information acquired from another device may be higher than that of each piece of the information including the position information, the map information, and the traffic information acquired by the device that generates the navigation information. In such a case, the device that generates the navigation information can generate navigation information with higher accuracy than that of the navigation information generated using each piece of the information including the position information, the map information, and the traffic information acquired by the device itself.
A device that searches a route to a destination and displays a route screen has been developed. When a user uses means of transportation, such as a train, along this route, for example, such a device turns OFF the power of a global positioning system (GPS) engine from a departure station to an arrival station.    Patent Document 1: Japanese National Publication of International Patent Application No. 2008-529443    Patent Document 2: Japanese Laid-open Patent Publication No. 2006-129019    Patent Document 3: Japanese Laid-open Patent Publication No. 2006-197536    Patent Document 4: Japanese Laid-open Patent Publication No. 2008-153773    Patent Document 5: Japanese Laid-open Patent Publication No. 2008-275544    Patent Document 6: Japanese Laid-open Patent Publication No. 2007-187620
However, there is a problem in that related technologies described above still fail to reduce the power consumption.
The problem will be explained using a specific example. For example, while the device that generates the navigation information is in operation, power is constantly supplied to a navigation module. As a result, the power consumption for the navigation module is not reduced. Therefore, the device that generates the navigation information described above fails to reduce the power consumption.
Furthermore, there is another problem in that, in the device that turns OFF the power of the GPS engine from a departure station to an arrival station, the navigation function is not available from the departure station to the arrival station.